Cylinder head mounts wont line up after top end rebuild

threefiddyone
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threefiddyone
Edited Date/Time 1/8/2016 7:56am
Hey guys i just rebuilt the top end on my 2004 CR250. Got the cylinder and head on and torqued to spec. The cylinder head mount bolts wont line up to bolt on. For those of you unfamiliar with the CR250 cylinder head mounts its got 2 plates with 2 bolts on the frame side and 1 bolt on the cylinder head side. I loosened all the other motor mounts to get maximum movement in the direction that i need to get it bolted up and it still wont line up by a hair. The only other thing that i can think of is to use a drill and bit to bore out the holes in the cylinder head mount plates so that everything will line up. It wont need too much adjustment.

Have any of you had this problem before? Do you think i should bore out the holes in the cylinder head mount plates?
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threefiddyone
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threefiddyone 1/6/2016 7:12pm
1/6/2016 7:12pm
Heres the OEM diagram in the first pic so you can see what it looks like. And the second pic you can see the bottom part of the mount and bolt.
Jmcd1988
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Jmcd1988 1/7/2016 4:03am
1/7/2016 4:03am
Did you have the cylinder decked? Or the head decked? If so then you "lowered" the top end.

I would drill out the mounts.
hellion
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hellion 1/7/2016 5:20am
1/7/2016 5:20am
If it lined up before, and you haven't had the cylinder decked, then something is going on. I wouldn't be boring out the mount plates, I'd be thinking more along the lines that something isn't together the way it should be.

The Shop

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ridinbeast932 1/7/2016 5:49am
1/7/2016 5:49am
Looks like the could be mistakenly flipped upside down. Are you sure they're right side up? Was your cylinder base gasket a different thickness?
threefiddyone
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threefiddyone 1/7/2016 5:57am
1/7/2016 5:57am
hellion wrote:
If it lined up before, and you haven't had the cylinder decked, then something is going on. I wouldn't be boring out the mount plates, I'd...
If it lined up before, and you haven't had the cylinder decked, then something is going on. I wouldn't be boring out the mount plates, I'd be thinking more along the lines that something isn't together the way it should be.
No i didnt have it decked. I had this problem the last time i did my top end, and when i loosened the lower motor mounts, i was able to wiggle it enough to get it to mount. I think the motor slowly settles in between top end jobs, which is also why it was hard to get motor mounts off both times. The cylinder sat flat on the cases, and the head went on straight. I guess it could just be in a slightly different position than it previously was.

Why do you advise not to adjust those holes? I know its not the preferred way but would it be detrimental in anyway? The holes are only off by a hair, so i would havento drill it out much.
jsmx97
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jsmx97 1/7/2016 6:04am
1/7/2016 6:04am Edited Date/Time 1/7/2016 6:04am
Silly question but you do know they are different left to right, correct?

Your frame could be stretching... one of the problems with aluminum frames. How many hours would you say are on your bike?
threefiddyone
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threefiddyone 1/7/2016 6:11am
1/7/2016 6:11am Edited Date/Time 1/7/2016 6:12am
jsmx97 wrote:
Silly question but you do know they are different left to right, correct? Your frame could be stretching... one of the problems with aluminum frames. How...
Silly question but you do know they are different left to right, correct?

Your frame could be stretching... one of the problems with aluminum frames. How many hours would you say are on your bike?
Yes I made sure they were the same way (left and right) when I was putting them back on. I tried the other way too just to see but they definitely dont work like that. My frame very well could be warped/stretched though. I probably have around 200 hours on the bike. Also, this crash may have tweeked things up a bit.
threefiddyone
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threefiddyone 1/7/2016 6:12am
1/7/2016 6:12am Edited Date/Time 1/7/2016 6:13am

It was bad enough to break my femur thats for sure.
hellion
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hellion 1/7/2016 6:37am
1/7/2016 6:37am
It won't hurt anything actually adjusting those holes a little. It's more that a company like Honda has impeccable fit and finish and this would indicate another problem to me.
FGR01
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FGR01 1/7/2016 7:07am
1/7/2016 7:07am
jsmx97 wrote:
Silly question but you do know they are different left to right, correct? Your frame could be stretching... one of the problems with aluminum frames. How...
Silly question but you do know they are different left to right, correct?

Your frame could be stretching... one of the problems with aluminum frames. How many hours would you say are on your bike?
Actually, steel frames are more known for stretching and sagging. Aluminum is more rigid and holds its shape longer. Aluminum will usually crack before it will stretch.

As for the OP, have you had this bike since new? Do you know the history of it? You say it was difficult getting the head stay bolt out and back in during the last top end also. Perhaps a previous owner decked the cylinder or shaved the head. There is no harm in oval'ing out the holes a few hairs to get clearance for the bolt. But before I'd do that I'd pull the 2 lower motor mount bolts and make sure they are not bent or something weird is going on down there. Also, inspect the frame very well and make sure there are no obvious cracks forming.
threefiddyone
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threefiddyone 1/7/2016 7:08am
1/7/2016 7:08am
hellion wrote:
It won't hurt anything actually adjusting those holes a little. It's more that a company like Honda has impeccable fit and finish and this would indicate...
It won't hurt anything actually adjusting those holes a little. It's more that a company like Honda has impeccable fit and finish and this would indicate another problem to me.
Alright thanks for the input. I never got a chance to do the top end before that wreck i posted above, so ive never actually had it fit perfectly.
threefiddyone
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threefiddyone 1/7/2016 7:17am
1/7/2016 7:17am
FGR01 wrote:
Actually, steel frames are more known for stretching and sagging. Aluminum is more rigid and holds its shape longer. Aluminum will usually crack before it will...
Actually, steel frames are more known for stretching and sagging. Aluminum is more rigid and holds its shape longer. Aluminum will usually crack before it will stretch.

As for the OP, have you had this bike since new? Do you know the history of it? You say it was difficult getting the head stay bolt out and back in during the last top end also. Perhaps a previous owner decked the cylinder or shaved the head. There is no harm in oval'ing out the holes a few hairs to get clearance for the bolt. But before I'd do that I'd pull the 2 lower motor mount bolts and make sure they are not bent or something weird is going on down there. Also, inspect the frame very well and make sure there are no obvious cracks forming.
I havent had it since new. It looked like the previous owner had looped it out or something, but im sure I did more damage to it in that crash that I posted above. I dont think the owner had much of any motor work done, i dont even think he ever took it on a track. I completely loosed the two lower motor mounts but I didnt think to pull them out and check them. Thanks for the help man!
harescrambled 1/7/2016 10:01am
1/7/2016 10:01am
You should also pull the swingarm pivot bolt and check it too.
Tim507
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Tim507 1/7/2016 6:34pm
1/7/2016 6:34pm
I was taught that all the bolts should be loose as you assemble the motor in the frame. This allows one to place all the pertinent bolts. Then you begin the tighten
harescrambled 1/7/2016 7:25pm
1/7/2016 7:25pm
That's how I do it, and the first one I torque is always the swingarm pivot bolt.
Lucky13FIST
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Lucky13FIST 1/7/2016 7:39pm
1/7/2016 7:39pm Edited Date/Time 1/7/2016 7:42pm
How much is it off? Is it a few thousands or more in the millimeter range? Drilling out the mounts isn't the first course of action you'd want to take. This sounds silly but maybe try removing the bolts and checking if they fit in the opposite hole. Do you have all the bolts loose and NOT torqued when trying to put the 3rd one in?
threefiddyone
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threefiddyone 1/8/2016 5:26am
1/8/2016 5:26am
Lucky13FIST wrote:
How much is it off? Is it a few thousands or more in the millimeter range? Drilling out the mounts isn't the first course of action...
How much is it off? Is it a few thousands or more in the millimeter range? Drilling out the mounts isn't the first course of action you'd want to take. This sounds silly but maybe try removing the bolts and checking if they fit in the opposite hole. Do you have all the bolts loose and NOT torqued when trying to put the 3rd one in?
It was off by about 2mm. After letting the motor sit loose overnight, I came back yesterday and the motor was able to wiggle a little more towards those mounts. I still had to drill out the bottom hole slightly, but after that everything slid in perfectly. Got all the motor mounts torqued and ready to go for the rest of the assembly.

Thanks for all of the input guys!

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ToolMaker 1/8/2016 7:46am
1/8/2016 7:46am
Lucky13FIST wrote:
How much is it off? Is it a few thousands or more in the millimeter range? Drilling out the mounts isn't the first course of action...
How much is it off? Is it a few thousands or more in the millimeter range? Drilling out the mounts isn't the first course of action you'd want to take. This sounds silly but maybe try removing the bolts and checking if they fit in the opposite hole. Do you have all the bolts loose and NOT torqued when trying to put the 3rd one in?
threefiddyone wrote:
It was off by about 2mm. After letting the motor sit loose overnight, I came back yesterday and the motor was able to wiggle a little...
It was off by about 2mm. After letting the motor sit loose overnight, I came back yesterday and the motor was able to wiggle a little more towards those mounts. I still had to drill out the bottom hole slightly, but after that everything slid in perfectly. Got all the motor mounts torqued and ready to go for the rest of the assembly.

Thanks for all of the input guys!
I'd have rather taken a round file and only removed material where needed once you've decided on opening the holes.
But that's just me,
threefiddyone
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threefiddyone 1/8/2016 7:56am
1/8/2016 7:56am
ToolMaker wrote:
I'd have rather taken a round file and only removed material where needed once you've decided on opening the holes.
But that's just me,
Looks like I need to invest in a round file then. Ive never used one. I didnt make the holes any bigger I just moved the edge of it out in one direction. Same end result different technique i guess.

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